Why do fair-skinned Brits burn while Swedes (for example) tan?

People from further north tend to have paler skins, the better to absorb the weak sunlight and trigger vitamin D production. After that any subtle differences in skin type are a matter of genetic inheritance.

"Your Celtic phenotypes - Brits with pale skin, freckles, red hair - will burn and never tan," says Mark Birch-Machin, reader in molecular dermatology at the University of Newcastle and a researcher for Cancer Research UK.

Brits of a less Celtic extraction may burn and then tan when young, but will pay for it heavily with wrinkles when older. "Each time you go out in the sun and get burned, you damage your DNA. Even before you get sunburned skin, you have damaged your DNA, so it is worse than it looks. You cannot say: 'I am safe until I become a lobster.' That is not true."

But Birch-Machin is dubious about races such as the Swedes having any real advantage over us in the tanning stakes. After all, our blood is extremely muddled up in Europe, and the British public is generally exposed to only a small sample of (famous) Swedes - some of whom may sport artificial tans of course.

"If you go out in the sun you may get skin cancer," he says. "But what is sure is that your face is going to look like an old sofa. You will have a 50-year-old face on a 30-year-old body, and particularly if you smoke."

James Scott, director of the genetics and genomics research institute at Imperial College London, thinks that from a genetic perspective, the British should be more likely to toast to a gentle brown than their cousins from more northerly latitudes.

The genetic differences among northern Europeans are minuscule, he says, and any golden glow from the Baltic could be, he says, an "observer artefact".

But he is not certain of that. "Either the genetics is subtly different in Swedes, such that they have blond hair and fair skin but the propensity to develop more melanin when they see the sun, " Professor Scott says. "[Or] maybe there is a form of conditioning in which the genes get set by environmental triggers in a particular sort of way."

• Science
• The science behind the news

ncG1vNJzZmivp6x7tbTEoKyaqpSerq96wqikaKuTnrKvr8RoaWloY2S3triOaWporJiewLixxKSqrJuZmruksdCunKysmaS7tIA%3D